A dangerous situation warning device is conventionally known which includes a vehicle neighborhood object detection device which detects an object on a front travel area, a danger latent area determination device which determines a danger latent area in which danger is latent, a danger degree processing device, and a warning output device (for example, see Patent Literature (PTL) 1). The danger degree processing device checks object information obtained by the vehicle neighborhood object detection device against the danger latent area obtained by the danger latent area determination device to determine a degree of danger with respect to an object which exists in the danger latent area. When the vehicle neighborhood object detection device detects a plurality of obstacles on the front travel area, the danger degree processing device sets the degree of danger for each of the obstacles and the warning output device displays the degree of danger for each of the obstacles. The warning output device is a head-up display, and displays a red frame surrounding the obstacle determined as having a high degree of danger at a position seen to be overlapping with the obstacle.